机械化保护性耕作的技术体系与应用效果

农业保护性耕作技术是当今国际上先进的农业生产技术.实施以残茬覆盖和免耕、少耕为主要内容的机械化保护性耕作,可以减少地表径流,避免土壤流失,降低土壤风蚀,增加土壤有机质含量,改善耕地肥力及理化性状,是实现保土、保水、保肥和保持生态环境的重要措施,是旱作农业实现可持续发展的重要途径.     

地下水超采区混合井回灌流量计算与效率分析

以试验数据为基础,对地下水超采区混合井回灌过程中井流量计算的方法进行理论归类,发现混合井回灌过程中的井流计算方法一般可按承压水井流计算方法进行;定量分析混合井单位流量变化过程,发现其回灌效率大于抽水效率;利用Grapher系统对不同流量回灌过程进行分析,得出利用混合井在超采区实施回灌其效率开始时虽存在衰减,但最终会趋于稳定。停灌后回灌井水位在数小时恢复到初始水位,说明回灌过程对开采井的滤水结构影响不大,管井水力传导仍然良好。     

Comparison of dot blot hybridization, polymerase chain reaction, and virus isolation for detection of bovine herpesvirus-1 (BHV-1) in artificially infected bovine semen.

Bovine semen samples spiked with bovine herpesvirus 1 (BHV-1) were used to compare dot blot hybridization, polymerase chain reaction (PCR), and virus isolation for detection of BHV-1 in bovine semen. The PCR amplification used primers targeting the BHV-1 thymidine kinase gene and a nucleic acid releasing cocktail (GeneReleaser); the PCR product was used as the DNA probe in dot blot hybridization; virus isolation was done in primary bovine fetal testis (BFT) cell cultures. Semen diluted 1:20 in tissue culture medium had the least cytotoxicity and inhibition of viral cytopathic effects in BFT cells, allowing detection of 1 TCID50/100 microL of BHV-1 suspension by virus isolation. The presence of foreign DNA such as bovine sperm DNA or salmon sperm DNA increased the sensitivity of dot blot hybridization in detecting BHV-1, allowing detection of 20,000 TCID50/100 microL of neat semen. The inhibition of PCR amplification of BHV-1 DNA in bovine semen was eliminated by diluting the samples 1:20 in tissue culture medium. The best PCR amplification was obtained when semen was diluted 1:20 and when a reaction buffer of pH 9.0, with 1.0 mM MgCl2 was used. Under these conditions, the PCR followed by ethidium bromide staining of agarose gels could detect 1 TCID20/100 microL of sample, whereas PCR followed by Southern blot hybridization could detect 0.01 TCID50/100 microL of sample.(ABSTRACT TRUNCATED AT 250 WORDS)     

叶面喷施抗蒸剂对苹果树水分状态的影响

研究了叶面喷施抗蒸剂对盆栽苹果水分状态的影响。结果表明：抗旱剂一号（主要成分为黄腐酸）可明显降低树体蒸腾（最低时为对照的３９．２１％）、提高气孔阻力（最大时为对照的２４３．９６％）和叶片水势（一般比对照提高０．２－０．４ＭＰａ、最大０．７ＭＰａ），并对叶温未产生明显的影响（变化一般小于１℃），有效作用期长达１５ｄ以上。在果树旱期喷施，可明显改善树体水分状态。腐殖酸效果不明显。     

研究型大学科研评价指标体系研究

进一步探讨了制定科研评价体系的原则、方法等,并结合目前我国研究型大学的实际情况初步提出了一套科研评价指标体系。     

实验性脾虚证大白鼠酶组织化学研究

将45只大白鼠随机分成3组，即实验组、治疗组及对照组，每组15只。以利血平致大白鼠脾虚证模型，分阶段捕杀动物，取肝脏、胃、十二指肠，用酶组织化学方法测定酸性磷酸酶(ACP)、碱性磷酸酶(ALP)、葡萄糖-6-磷酸酶(G-6-Pase)活性的变化。结果表明：实验组、治疗组、正常对照组各酶活性均发生了变化，在第7天、第14天时组内各酶存在着动态学上的变化。治疗组各酶活性接近正常对照组，说明四君子汤具明显的治疗作用。     

北疆苜蓿属植物繁育系统的研究

采用等位酶技术，对北疆苜蓿属植物种群的繁育系统进行了研究。结果表明，北疆苜蓿属植物种群为外繁育系统，黄花苜蓿、多变苜蓿、紫花苜蓿基因组成中杂合体过多，均保持较低的自交结实率。参试苜蓿属植物表现某种程度的内繁育衰退现象，地理或生殖隔离等因素可能是导致个别种群出现内繁育衰退现象的原因之一。对北疆苜蓿属遗传资源保护时，既要选择遗传基础丰富的种和种群以保持最多的遗传变异，还要注意选择具有不同等位的种群以保持原有的基因和基因频率。     

电算化会计信息系统下内部控制研究

本文对会计电算化发展中存在的一些问题提出了对策与建议，并针对财会工作的自身特点，从程序控制和制度控制两个方面阐述了电算化会计信息下的内部控制方法。     

Blackhead disease (Histomonas meleagridis) aggravated in broiler chickens by concurrent infection with cecal coccidiosis (Eimeria tenella).

The effect of concurrent cecal coccidiosis infections on severity of Histomonas meleagridis (blackhead disease) in chickens was investigated in a series of experiments. Cecal lesions from H. meleagridis were severe in all inoculated control groups and did not appear to be affected by the introduction of Eimeria tenella infection. However, the severity of liver lesions and number of birds positive for liver lesions of H. meleagridis increased significantly with the presence of E. tenella. The increase was similar when 10(3) or 10(4) oocysts of E. tenella were given and was the same when oocysts were given at the same time as H. meleagridis or 4 days prior. The liver lesions increased directly as doses of H. meleagridis increased from 7.5 x 10(3) cells to 30, 100, or 300 x 10(3) when E. tenella was given along with H. melelagridis but not when H. meleagridis was given alone. Administration of a live coccidiosis vaccine containing very low levels of E. tenella also gave a significant boost to liver lesions but at a much lower level than that observed with larger doses of E. tenella. The positive relationship between infections of cecal coccidiosis and H. meleagridis in chickens suggests that such dual exposure may contribute to increased clinical outbreaks of blackhead disease in chickens under field conditions.     

模拟发电机组专用可控硅直流调速系统

本文从分析同步发电机原动系统基本数学模型入手，提出了一种实现同步发电机原动系统仿真的专用可控硅直流调速系统及其实用装置。该控制系统采用有差调节的模拟调速器，水汽管道特性模拟、自平衡特性模拟和集成块模拟触发器，以及过流与超速保护，并可实现有差－无差调节的转换。